Friday, January 16, 2015

I joined
Kay’s lab last winter, for a two-year post-doc. My name is Agathe (in French,
you would pronounce the A as you say it when the doctor is looking inside your
mouth, and then pretend there is no H after the T, as it is usually silent in
our beautiful language).

Ok, enough
about French pronunciation. I’ve been in the Maasai Mara since last September, shameon me for not writing a blog post before, no excuse.

So, as you probably know, as primates, we are one of the species that
can claim one of the biggest relative brain size among mammals. However, you
would be surprised by what some birds can do, or even honeybees (Komischke et
al, 2002). But, this depends on what kind of cognitive tests you are
considering. In fact, cognition can be divided in two categories: physical and
social cognition. While the first helps us deal with inanimate objects, we are
able to understand our conspecifics intentional actions, perception and
knowledge thanks to the latest (Herrmann et al, 2008). Of course, social
cognition is most useful when living in a big society, which means frequent
encounters with conspecifics. As a matter of fact, social complexity could be
what drove individuals to have bigger and bigger brains by evolution (Byrne
& Whitten, 1988). This is because living in a complex society enforced the
need to understand its social rules, or to predict/understand the intentions of
your conspecifics, especially if they’re higher ranking. As an example, when
you are a middle ranking animal, you better be able to tell if that high ranking
female approaching your kid is going to bite its head off, or just sniff it on
her way and go. Or, before you come to rescue your BFF who’s being bullied, you
want to make sure that his tormentor is not higher ranking, because he will
remember you next time…

You probably know by now how great our hyenas
are, and like monkeys, they are able to recognize any member of their clan.
Therefore they can remember their social status and choose to join someone in a
brawl based on previous interactions and social affinity (Holekamp et al, 2007).
Overall, they meet the criteria to fit in the social intelligence hypothesis.

On the other hand, we know very little
regarding their physical cognition (however, see previous work on our hyenashere), mostly because majority
of that research focuses on primates. The social intelligence hypothesis
predicts a high level of physical cognition along with social cognition. The
key is to choose a task that can be done by several species, so that a wide
comparison between species is possible. Let’s forget about IQ tests right away,
only a chimpanzee would give the pen back when he’s done, and even a rather civilized baboon would eat it. Behavioral
flexibility, the ability to adapt one’s behavior to solve a problem, is a good
measure of general intelligence and can be adapted through various tasks.

The hard part was to choose a task that hyena
could solve without the use of hands, unlike their primate friends. Moreover,
wild hyenas are very cautious toward man-made objects, hence I chose a task
that they could do in several steps, to eliminate any bias of novelty on their
ability to solve the task. So, to test their ability to display flexible
behavior, I’m using a reversal learning test where the hyenas have to pull
ropes to get access to meat, as a reward. They first have to learn to
discriminate between two colors (black versus yellow), one associated with the
reward, the other one associated with the absence of that reward. Once they
have learned that, the rewarded and the non-rewarded colors are reversed and
they have to suppress one behavior in favor of another to get the meat.

On this video: from the inside of the box: Decimeter, a subadult high-ranking female, comes and pulls the rope. It's her first time though, so she is kind of freaked out instead of taking the meat right away.

Conducting an experiment on wild hyenas takes
time, especially when I have to find them across their wide territory and get
them to interact with the device. After a very long habituation phase, I have
now started the learning phase, trusting that my beloved subjects will learn it
quickly (because I believe that they are indeed smart). Then, the best part
begins: reversal learning!

Unlike Decimeter, KENG is used to the box and loves it. You can see that she already got the meat on the right side. Here she is trying to pull the yellow rope, but the left tray is blocked : she now has to learn that only the black rope will get her meat!

Another time I’ll tell you how it went with
lions (we could not find any hyenas that day, and I was curious…).

speaking of Hyenas and ropes, i remember (yet again) a documentary where scientists were testing group communication intelligence of some sort. and they set a board on the ground outside a metal cage with two ropes on each end. the board had several bowls of food in them near the center.

The board was presented in such a way that the hyenas had to work together to pull the ropes at the same time or the board would not move towards the cage in the right angle to gain them access to food. If they pulled on one end before the other the other end would sway out away from the cage and its rope would no longer be reachable from the cage. leaving the food in the middle of the board inaccessible as well.

Hyenas not only were faster at discovering the timing and teamwork required to successfully complete this task and get the food than chimpanzees. But they were also had a higher success rate in their attempts.

Help Support the Research

You can help support our research by making a donation to the Hyena Research Fund at MSU. Your contributions provide necessary resources for the students and scientists to continue our work. Use the link below to make a donation or contact MSU for additional details.